سامانه هوشمند پايش پوشش برف در حوضه سفيدرود

The Sefidrood basin, one of the most critical water resources in the countryʹs northwest, plays a vital role in meeting agricultural an‎d drinking water needs; thus, the viability of this basin is highly dependent on snow reserves in high-altitude areas. However, in recent years, climate change an‎d global warming have altered precipitation patterns an‎d accelerated snowmelt. Accordingly, the present study aimed to develop an intelligent, practical system in MATLAB to enable accurate, automated, an‎d timely monitoring of snow-cover changes using remote-sensing data for optimal water-resource management. In this regard, daily images from the MODIS sensor aboard the Terra an‎d Aqua satellites were used for the period from 2003 to 2022 (1382 to 1401 according to the IRI calendar). To accurately extract snow-covered areas, the Normalised Difference Snow Index (NDSI) was applied, an‎d to mitigate cloud-cover errors, spatial an‎d temporal filters were applied to the data. Time-series analysis indicates that although snow cover in this basin exhibits strong interannual fluctuations, its overall long-term trend is decreasing. The findings show that, contrary to previous patterns, the most severe rate of snow-cover reduction has occurred during the core winter months (January an‎d February; equivalent to Dey an‎d Bahman on the IRI calendar). Although January (Dey on the IRI calendar) still accounts for the largest share of snow accumulation, it has become less stable. Moreover, the declining trend in spring indicates earlier snowmelt an‎d a shorter snow cycle. Spatially, the central an‎d southern parts of the basin have experienced the most significant decline, while the northern an‎d eastern highlan‎ds of the Alborz range have shown more stable conditions. These changes indicate a transition of the basin’s hydrological regime from snow-dominated to mixed regimes, intensifying the risks of spring floods an‎d summer water shortages. Finally, the system developed in this study, capable of distinguishing sub-basins, is an efficient tool for water resource managers to regulate dam reservoirs an‎d manage potential crises. It is recommended that high-altitude snow-covered areas be prioritised as strategic zones for protection.

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